Candice

General Info - Candice has a team of Ice types, which sort of suits her home. Although, her Pokemon pretty much suck. Bring a good Fire type and this should be a very easy battle. If you don't have a Fire type then bring a Fighting type. She is the first gym leader to have more than 3 Pokemon, at least.

Lv38 (Grass/Ice) - Snover has a 4x weakness to Fire, so take it out quickly and proceed. It's Snow Warning will cause the weather to change to Hail, though. Just thought I'd let you know.

Lv38 (Dark/Ice) - If you have a Fighting type, that is the best choice, other wise a Fire type will do. Sneasel does have high attack and speed, but that shouldn't be too much of a problem.

Lv40 (Fighting/Psychic) - Medicham is the only non-Ice type on Candice's team, and is probably her best Pokemon. If it gets in a few Bulk Ups, it can be very dangerous. You need to take it out before it gets 2 Bulk Ups in, so use a Flying type like Staraptor for that job.

Lv42 (Grass/Ice) - Take out Abamasnow just like you did Snover. Any Fire type should OHKO it, but watch out for Wood Hammer if you use a different type.